Collapsible boring head for mining machines



Nov. 29, 1955 J. 5. ROBBINS ETAL 1,

COLLAPSIBLE BORING HEAD FOR MINING MACHINES Filed June 30, 1954 5 Sheets-Sheet l v- 9 J. 5. ROBBINS ETAL COLLAPSIBLE BORING HEAD FOR MINING MACHINES Filed June 30, 1954 5 Sheets-Sheet 2 wwm y w. W? W W W \N. mm a w w; kc W w W 2Q d a m w fi m \h 7/ I W F & v ii NW \N u c MN NW NOV. 1955 J. 5. ROBBINS EI'AL. 2,725,222

COLLAPSIBLE BORING HEAD FOR MINING MACHINES Filed June 30, 1954 5 Sheets-Sheet 3 5 Sheets-Sheet 4 Nov. 29, 1955 J. s. ROBBINS ETAL COLLAPSIBLE BORING HEAD FOR MINING MACHINES Filed June 30, 1954 ,55% lg fg 7 A N i i n S: W U/ Wm Q: h m I A =5 a 2 IE: 2 1 6 l m mum 4 Nov. 29, 1955 J. 5. ROBBINS ETAL COLLAPSIBLE BORING HEAD FOR MINING MACHINES 5 Sheets-Sheet 5 Filed June 30, 1954 w a 2W L| v/ 1 HI M .2 \g 17/2, aw 4 -0 3 W n 4 4 INVENTORS James ,5. jfoz'ns ite rates Patent Ofifice 2,725,222 Patented Nov. 29, 1955 COLLAPSIBLE BORING HEAD FOR MINING MACHINES James S. Robbins and Carl A. Wilms, Chicago, 111., as-

signors to Goodman Manufacturing Company, Chicago, 111., a corporation of Illinois Application June 3-1), 1954, Serial No. 440,414

4 Claims. (61. 262-7) This invention relates to improvements in mobile mining machines of the boring type wherein one or more rotary boring heads having a plurality of generally radial cutter arms are forced into a face of standing material such as coal. Since mining machines of the type mentioned operate within the vertical and lateral dimensions of the bore formed by the cutter head or heads of the machine, it is desirable to provide means for reducing the outer diameter of the boring head when the machine as a whole is to be withdrawn from the bore and transported from place to place in the mine. To this end, various means have heretofore been devised for collapsing or retracting the outer ends of the radial arms of the boring head when desired. This involves a difficult problem, because each of the radial arms has a plurality of forwardly projecting cutter supports of sufiicient length and strength to form a plurality of circular kerfs in the working face.

The principal object of the present invention is to provide an improved construction for collapsing the radial arms of a boring head to reduce the maximum working diameter of the head to a minimum. Other objects of the invention will appear from time to time as the following description proceeds.

The invention may best be understood by reference to the accompanying drawings, in which:

Figure 1 is a front view of a cutter head constructed in accordance with our invention, showing the hinged radial arms thereof in fully extended working position.

Figure 2 is a view similar to Figure 1, but showing the radial arms in their collapsed position of minimum diameter.

Figure 3 is a longitudinal vertical section of the cuttei head with the radial arms as shown in Figure 1, together with its bearing support forming part of a mining machine.

Figure 4 is a section similar to Figure 3, but showing the radial arms in their collapsed position as in Figure 2.

Figure 5 is an enlarged detail section taken on line 55 of Figure 3.

Figure 6 is an enlarged fragmentary detail of the hinge structure, viewed from the front of the head as seen in Figure 1.

Figure 7 is an enlarged fragmentary view of the hinge structure taken generally on line 7-7 of Figure 1.

Figure 8 is a longitudinal vertical section of a variant form of cutter head, together with its bearing support forming part of a mining machine.

Figure 9 is a front view of the cutter head shown in Figure 8, but with the radial arms in their collapsed position of minimum diameter.

Referring to details of the embodiment of the invention shown in Figures 1 to 7 inclusive, a single boring head is indicated at 10 the main elements of which consist of a hub 11 having three similar, generally radial cutter arms 12, 12, 12 hinged thereto, and three relatively short cutter arms 13, 13, 13 each fixed thereto intermediate the hinged arms 12. The hub 11 is hollow, and is fixed on the front end of a hollow shaft 14 suitably journalled as by bearings 15 in a support 16 forming part of the mining machine. A forwardly projecting burster cone 17 may be fixed as usual at the front end of the hub.

The hinged cutter arms 12 are each pivoted on a pin 18 carried transversely adjacent the front face of hub 11 by a pair of cars 19, 19 formed integrally therewith (see Figures 6 and 7). Preferably the longitudinal axis of each of said arms and its pivotal mountings are slightly offset circumferentially of the hub in the same direction relative to the axis of rotation of the hub, so as to cooperate with the mechanism for effecting hinged adjustment of said arms as will presently be described.- Each of said radial arms has one or more forwardly projecting cutter brackets 20 suitably mounted on its front face, and having a plurality of cutter bit holders 21 along their front edges, each having bits 22 arranged for cutting a circular kerf in the working face. Each of the shorter intermediate arms 13 also has similar cutter brackets 23 projecting forwardly therefrom, in position so that they do not interfere with the forward hinging movement of the longer cutter arms 12 and the cutter brackets carried thereby. Further description of the means for mounting the cutter brackets on their respective arms may be omitted, as such bracket mounting means forms no part of the present invention.

Each of the hinged cutter arms 12 has a worm segment 24 concentric with its inner hinged end, with its toothed portion extending through an angle of slightly more than and facing inwardly and rearwardly of its pivotal mounting so that said segment is fully enclosed within the hub when the arm is extended into its normal full-diameter cutting position as shown in Figures 1 and 3.

Each worm segment 24 is engaged by a worm 25 on a spindle 26, rotatably supported in the hub by bearings 27, 28 spaced on opposite ends of the said worm. The spindles are disposed in slightly off-centered relation to the axis of the hub, and have pinions 29, on their inner end meshed with a series of teeth 30 formed along the front end of a control rod 31 which is reciprocably mounted in and concentric with the hollow drawn shaft 14. The control rod may be actuated by any suitable power means (not shown) at the rear end of the drawn shaft. The pinions 29 and the teeth 30 thus form in effect three rack and pinion devices for simultaneously effecting angular adjustment of the hinged arms 12 by rotation of the worms 25, and worm gear 24, the segments on said arms, as will be seen by comparison of Figures 3 and 4. When the arms are fully extended as shown in Figure 3, the cutter brackets project forwardly in their normal kerf cutting or boring position. When the arms are swung forwardly into collapsed position as shown in Figure 4, it will be seen that the cutter brackets become folded toward the tapered burster cone 17 in compact relation with each other and with said cone so as to present a cutter head of minimum diameter, substantially equal to the overall diameter of the hub 11.

In the variant form of cutter head shown in Figures 8 and 9, the general arrangement of hub 41, hinged arms 42, shorter arms 43, drive shaft 44, burster cone 45 and cutter brackets 46 and 47 is similar to the corresponding parts of the form of cutter head shown in Figures 1 to 7, excepting that each of the hinged arms 42 and the worm geared connections thereto are disposed in radially centered planes relative to the axis of rotation of the hub, instead of slightly offset planes. In the variant form of Figures 8 and 9, each worm 48 which engages the worm segment on its respective hinged arm is fixed on a spindle 49, rotatably mounted as before in the hub, but each spindle has a bevel gear 50 on its inner end meshed with a bevel gear 51 on a control shaft 52 rotatably mounted in and extending along the hollow drive shaft 44. Thus, the hinged adjustment of the arms 42 is effected by rotation of the control shaft 52, instead of by reciprocable movement of a control of the kind employed in the first described form shownin Figures 1 to 7. In other respects, the operation of the two forms is substantially alike.

We claim:

1. In a boring head for mining machines a hollow hub, a hollow drive shaft for said hub, a plurality of arms hinged to said hub at their inner ends for swinging movement in planes extending generally radially of and including the axis of rotation of said hub, each of said hinged arms having a plurality of bit-carrying supports mounted on and extending forwardly therefrom for cutting a plurality of concentric kerfs in a working face, and means for adjusting said hinged arms toward and away'from the axis of rotation of said hub, comprising a worm segment fixed on each of said arms concentric with its hinged connection to said hub, a worm meshed with each of said segments and rotatably mounted in said hub on an axis extending generally radially of the axis of rotation of said hub, and means in said hub for simultaneously rotating said worms, said means including a control rod passing through and concentric with said hollow drive shaft.

2. The structure of claim 1, wherein each of the worm segments is disposed rcarwardly and inwardly of the hinged connection of its respective arm and the hub, so as to be fully enclosed within said hub when its respective arm is fully extending into cutting position.

3. The structure of claim 1, wherein the means in the hub for actuating the worms includes a pinion rotatable with each worm and meshed with a toothed rack on the control shaft reciprocably mounted in the hollow drive shaft.

4. The structure in accordance with claim 1, wherein the means for actuating each of the worms includes a bevel pinion rotatable with each worm and meshed with a common bevel pinion on a control shaft rotatably mounted in the hollow drive shaft.

References Cited in the file of this patent UNITED STATES PATENTS 530,510 Elliott et a1. Dec. 11, 1896 1,589,508 Boynton June 22, 1926 2,324,679 Cox July 20, 1943 2,621,898 Brodhead et al. Dec. 16, 1952 

